Liquid cooled grinding wheel



1956 J. A. HARRINGTON 2,774,201

LIQUID COOLED GRINDING WHEEL Filed Nov. 4, 1954 INVENTOR.

nited States Patent G LIQUID COOLED GRINDENG WHEEL John A. Harrington, Minneapolis, Minn, assignor to Continental Machines, Incorporated, Savage, Minrn, a corporation of Minnesota Application November 4, 1954, Serial N 466,717

9 Claims. (Cl. 51-267) The present invention relates to grinding wheels; and in particular, it relates to a novel and improved and apparatus for efiecting internal cooling of the wheel and the work, during the operation of the wheel.

The present invention effects cooling of a grinding wheel by percolation of a liquid coolant radially of the wheel, through the interstices of the homogeneous body thereof, from the center of the wheel to the peripheral face thereof, uniformly throughout the entire circumference and axial length of the wheel by the utilization of centrifugal force developed as a result of high speed rotation of the wheel.

An object of my invention is to provide a uniform distribution of a regulated or controlled supply of coolant throughout the entire circumference and axial length of a grinding wheel.

In most cases, involving the radial distribution of a liquid coolant by centrifugal force throughout the axial length and circumference of a grinding wheel, the best cooling is efiected by a regulated or controlled supply of coolant to the wheel, which cooling, in particular, is best accomplished by a very slow drip-like feed so that a greater surface area of the coolant may be presented at the point of grinding. With respect to grinding wheels now known in the art, the characteristics of centrifugal force are generally not recognized; in particular, the characteristic that as soon as the liquid coolant is released from a restraint, it moves directly in a straight line, under centrifugal action, radially from the point where the restraint is released. If in radial distribution of the coolant, in a grinding structure involving radial distribution outwardly through a plurality of axially spaced radially directed passages or openings, all or a plurality of said passages are fed from a common axially extended cavity or passage, the radial openings or passages closest to the source will receive all or most of the supply, if regulated. Uniform circumferential and axial distribution of the coolant could be effected, in such a case, only by a steady, solid flow of coolant to the interconnected axially spaced points of radial distribution, which condition is seldom, if ever, desirable.

Therefore, it is another object of the present invention to provide, in a grinding wheel structure including a grinding wheel having a central axially extending cavity, coolant, which may be regulated as to supply, being delivered through axially extending passages of different lengths to all of the various axially spaced points within the cavity of the wheel, so that even distribution of a regulated supply of coolant is effected throughout all axially and circumferentially spaced areas of the wheel.

it is a further object of the present invention to provide in the art or" grinding, a method of supplying coolant to a grinding wheel having a central axially extending cavity, wherein the coolant is properly restrained against centrifugal action until it reaches the proper point for radial delivery or distribution within the cavity of the wheel, to effect uniform. distribution of the coolant throughout all axial and circumferential spaced areas of the wheel.

2,774,201 Patented Dec. 18, 1956 These and other objects and advantages will be apparent in the course of the following specification and claims, reference being had to the accompanying drawings wherein:

Fig. 1 is a fragmentary view in front elevation, with some parts broken away, of my invention;

Fig. 2 is a view in vertical section taken substantially on the line 22 of Fig. 1; and

Fig. 3 is an enlarged fragmentary view in horizontal section taken substantially on the line 33 of Fig. 2.

Referring more particularly to the drawings, wherein like parts will be indicated by the same numeral, the numeral 10 indicates a conventional grinding wheel composed of any well known abrasive substance, having any desired grain size, and a suitable bonding substance of any well known kind, and having a porous homogeneous body. Wheel 10 has an axially extending bore or cavity 11. A hub 12 positioned in and extending generally through cavity 11 comprises a pair of telescoped axially extending annular hub members 13 and 14, and a pair of radially outwardly projecting circumferentially extending flanges 15 and 16 integral with the telescoped hub members 13 and 14, respectively.

For the purpose of securing wheel 16 to a spindle 17 having a tapered end portion 18 and a threaded end 19 disposed axially outwardly of tapered end 18, hub member 13 is provided with a tapered opening '20 corresponding to the taper of end portion 18 of the spindle 17 and an axially outwardly opening recess 21 at the smaller end of the tapered opening 20 which provides a shoulder 22. Hub member 13 is held fast on the tapered end 18 of the spindle 17 by means of a nut 23 threaded on the end 19 which engages the shoulder 22. Hub member 13 is positioned on spindle 17 with the circumferentially extending flange 15 disposed axially inwardly adjacent the inner end of hub member 13. Fastening means comprising circumferentially disposed bolts 24 extend between the separate portions of hub 12, and specifically extend axially through hub member 14 and are threaded into circumferentially extending flange 15 adjacent the inner end of hub member 13. Fastening means 24 hold the separate portions of hub 12 together and hold the circumferentially extending flanges 15 and 16, together with friction washers 25, in friction locking engagement with the opposite side faces 26 and 27 of the wheel 16.

A pan-shaped member 28 having a rim '29 releasably secured to the circumferentially extendingflange 16 by threaded bolts 3t? defines a coolant-receiving cavity 31 adjacent the axially outwardly disposed side 32 of the hub 12. A conduit 33 extends through an aperture 34 in pan-shaped member 28 to open axially into the coolantreceiving cavity 31 and is adapted to be connected to a source of coolant, not shown in the drawings, which may be regulated or controlled to supply a very slow drip-like feed of coolant to the cavity 31.

The inner end 34 of hub member 14 is spaced axially outwardly from the circumferentially extending flange 15 to define a space 35.

The periphery 36 of axially extending hub member 14, radially outwardly disposed with respect to axially extending hub member 13, is contiguous the inner cylindrical surface 37 of the wheel 10. Hub member 14 has a plurality of identical circumferentially disposed groups or series 38 of several axially extending passages 39 and an axially extending passage 40, which is the last passage of the series, formed therein. Passage 39 and passage 40 of each group 38 are circumferentially spaced and of difierent lengths; the passages opening at their ends 41 into the coolant-receiving cavity 31 and at the opposite ends 42 terminating in axially and circumferentially spaced points in the hub member 14 of hub 12. The passages 39 and passage 40 of each group 38 are arpassages 43.

tending passages 39 adjacent their closed ends 42 to the periphery 36 of hub member 14 and opening, adjacent the inner surface 37 of wheel 10. Radially extending passages 43 are of smaller diameter than the axially extending passages 39 and 40. Hub member 14 also has a plurality of axially extending passages 44 formed therein, one of which extends from each of the passages 40 to the space 35. Passages 44 are of approximately the same diameter and length as the radially extending The passages 39 and passage 40 of each series 33 are adapted to uniformly distribute the coolant in the hub 12 along the axial length of the wheel 10, and the disposition of the identical series 38 of the passages 39 and 40' elfects this axial distribution of coolant uniformly about the circumference of the hub 12. Thus, the cool ant is delivered from the coolant-receiving cavity 21 -'through the axially directed passages 39 and 40 to all a the various axially spaced points Within the cavity 11 of the wheel until delivered to said points, the cool ant is restrained against centrifugal action; and from said pointsjthe coolant is delivered through the radially di-' rected passages 43 and space 35 to the wheel 10, so that even distribution of coolant is effected throughout all axially and circumfe-rentially spaced areas of the wheel 10.

My invention not only effects the aforesaid uniform distribution of the coolant, but by restraining the coolant against centrifugal action until it reaches the proper point for distribution, the supply of coolant to the wheel 16 maybe efiectively regulated to accomplish the most satisfactory cooling of the wheel. In other words, my invention is adapted to achieve regulation of the supply of coolant to the wheel 10 together with a uniform distribution thereof throughout all the axially and circumferentially spaced areas of the wheel 10. t

My inyention has been built and tested' and found to accomplish: all of' the afore-mentioned objectives and advantages. It will be obvious to those skilled in the art that my invention may be modified'by many substitutions and equivalents and that this disclosure is intended to be illustrative only. Therefore, I intend to be limited solely by the scope of the appended claims.

What I claim is:

lLIn combination with a grinding wheel having a central axially extending cavity, a pair of axially spaced oppositely disposed flanges engaging, the opposite side faces of the Wheel and adapted to mount said wheel on a spindle for rotation therewith,'structure defining an annular enclosed coolant-receiving cavity disposed ad 'jacent one side of the cavity of said Wheel, structure defining atplurality of cireumferentially spaced axially extending passages of different lengths extending from said coolant-receiving cavity into said central axially extending cavity of the wheel, and structure defining a t plurality of radially extending passages leading from said axially extending passages to the inner surface of said wheel, each axially extending passage having only one radially extending passage leading therefrom,the junction V of each axially extending passage with its one associated radially extending passage being adjacent the end of the V former which is opposite said coolant-receiving cavity,

fwhereby coolant may he controllably delivered from said coolant-receiving cavity to said central axially ex tending cavity of the wheel with uniform axial and circumferential distribution thereof through said axially extending passages and from said" axially extending pas- 7 defining an' annular coolant-receiving cavity disposed adjacent one side of said hub, said hub having a plurality of circumferentially spaced axially extending passages of different lengths formed therein, said passages opening at one end into said coolant cavity and" a at their opposite ends terminating at axially and circumprising a pair of telescoped axially extending annular t ferentially spaced points in said hub, and said hub having a plurality of radially extending passages formed therein leading from said axially extending passages to the'periphcry of the hub, each axially extending passage having only one radially extending passage leading therefrom, the junction of each axially extending passage with its one associated radially extending passage being adjacent its closed end, whereby coolant may be controllably delivered from said coolant-receiving cavity to said hub with uniform axial and circumferential distribution thereof through said axially extending passages and from said hub to the grinding wheel through said radially extending passages.

3. In combination with a grindingwheel having a central axially extending cavity, a hub positioned in said cavity and adapted to be mounted on a spindle for rotation therewith, a pair of'axially spaced oppositely disposed flanges carried by said hub and frictionally engaging the opposite side faces of the wheel torrnount said wheel on the hub, structure defining an annular coolantreceiving cavity disposed adjacent one side of said hub, said hub having a plurality of circumferentially disposed like groups of several circuniferentially spaced axially extending passages of different lengths formed therein, said passages-being spaced uniformly from the axial center of said hub andspaced radially inwardly from the periphery thereof, the circumferentially'spaced axially extending passages of each group opening at one end into said coolant cavity and at their opposite ends terminating at axially spaced points in said hub, and said hub having aplu-rality of radially extending passages of smaller diameter than said axially extending passages formed therein leading from said axially extending passages to the periphery of the hub, each axially' extending passage having only one radially extending passage leading therefrom, the junction of each axially extending passagewith its one associated radially extending passage being adjacent its closed end, whereby coolant may be controllably delivered from said coolant-receiving cavity to said hub with uniform and axial circumferential distribution thereof through said axially extending passages and from said hub to the grinding wheel through said radially extending passages. a

4. A grindingaassembly comprising a grinding wheel having a central axially extending cavity; a hub comhub members positioned within said cavity, and a pair of radially outwardly projecting circumferentially extending flanges integral with 'said'telescoped hubrmembers, one radially outwardly projecting flange formed'with each hub member at one end thereof; a spindle having a tapered portion and a threaded end axially outwardly of said portion; said radially inwardly disposed axially extending hub member having a tapered opening corresponding to the taper on said shaft and an axially outwardly openingrecess at the smaller end 'of said tapered opening providing a shoulder; a nut engageable with said' threaded portion and said shoulder totrnount said radially inwardly disposed telescoped hub member on the tapered portion of said spindle for rotation therewith with the 'circumferentially extending flange integral therewithdisposed axially inwardly adjacent its'inner end; fastening means extending between said hub members to connect a them together and to hold said circumferentially extending flanges in frictional locking engagement with the opposite side faces of said wheel; said radially outwardly disposed telescoped hub member having a plurality of identical circumferentially disposed groups of several circumferentially spaced axially extending passages of different lengths formed therein; the passages of each group being progressively greater in length, all of said passages being spaced uniformly from the axial center of said spindle and spaced radially inwardly from the periphery of said radially outwardly disposed hub member; and said radially outwardly disposed hub member having a plurality of radially extending passages formed therein leading from said axially extending passages to the periphery of the hub, each axially extending passage having only one radially extending passage leading therefrom, the junction of each axially extending passage with its one associated radially extending passage being adjacent its closed end.

5. The structure defined in claim 5, wherein the inner end of said radially outwardly disposed hub members is spaced axially outwardly from the circumferentially extending flange integral with said radially inwardly disposed hub member to define an annular space, and in further combination, said radially outwardly disposed hub member having formed therein a plurality of axially extending passages in communication with said annular space, one of said last-mentioned passages being disposed in each of said groups, a pan-shaped member having a rim releasably secured to the circumferentially extending flange integral with the radially outwardly disposed hub member to define a coolant-receiving cavity adjacent the axially outwardly disposed side of said hub, and a conduit extending through said pan-shaped member and opening axially into said coolant-receiving cavity and adapted to be connected to a regulated source of coolant, the passages of each group opening at one end into said coolantreceiving cavity.

6. In the art of grinding, the method of supplying coolant to a grinding wheel having a central axially extending cavity comprising controllably delivering the coolant to a plurality of circumferentially disposed points within said cavity, providing a radial outlet for said coolant from each of said points with each outlet being axially spaced from each adjacent outlet, and discharging the coolant radially from said points to said wheel to provide uniform circumferential and axial distribution of said coolant to said wheel.

7. In a structure of the class and for the purpose de scribed, a mounting hub having a generally cylindrical outer surface adapted to be received in the axial bore of a porous grinding wheel, means for anchoring said grinding wheel to said hub for rotation therewith, structure defining an annular coolant-receiving cavity disposed adjacent one side of said hub, said hub having a plurality of circumferentially spaced axially extending passages formed therein which open at one end into said coolantreceiving cavity, and said hub having a plurality of radially extending passages leading from said axially extending passages to the periphery of the hub, each axially extend-- ing passage having at least one radially extending passage leading therefrom, adjacent axially extending passages each having a diiferent length between said coolantreceiving cavity and one radially extending passage associated therewith and being devoid of radial outlet between said coolant-receiving cavity and said one associated radially extending passage.

8. In the art of grinding, the method of supplying coolant to a grinding wheel having a central axially extendin cavity comprising controllably delivering the coolant to a plurality of circumferentially disposed groups of circumferentially and axially spaced points within said cavity, providing a radial outlet for said coolant from each of said points with each outlet of a group being axially spaced from the other outlets of the same group, there being a substantially equal axial and circumferential distribution of points within said cavity, and discharging the coolant radially from said points to said wheel to provide uniform circumferential and axial distribtuion of said coolant to said wheel.

9. In a structure of the class and for the purpose described, a mounting hub having a generally cylindrical outer surface adapted to be received in the axial bore of a porous grinding wheel, means for anchoring said grinding wheel to said hub for rotation therewith, structure defining an annular coolant-receiving cavity disposed adjacent one side of said hub, said hub having a plurality of circumferentially disposed groups of circumferentially spaced axially extending passages formed therein which open at one end into said coolant-receiving cavity, and said hub having a plurality of radially extending passages leading from said axially extending passages to the periphery of the hub, each axially extending passage having at least one radially extending passage leading therefrom, axially extending passages of the same group each having a diiferent length between said coolant-receiving cavity and one radially extending passage associated therewith and being devoid of radial outlet between said coolantreceiving cavity and said one associated radially extending passage, there being a subtsantially equal number of axially extending passages of each length as measured between said coolant-receiving cavity and each of said associated radially extending passages.

References Cited in the file of this patent UNITED STATES PATENTS 260,336 Thayer June 27, 1882 298,046 Weaver May 6, 1884 376,854 Cavert Ian. 24, 1888 2,167,282 Murphy July 25, 1939 2,535,184 Wilson Dec. 26, 1950 FOREIGN PATENTS 511,547 Germany June 30, 1929 

